Abstract: An internal combustion engine having its cylinders tilted at an angle of less an than 90 degrees relative to a vertical axis is provided with a oil drain mechanism for drainign excess oil that collects when the engine stops. For this purpose, an oil drain hole, which communicates with an interior of the piston body to drain the lubricating oil, is formed in the inner wall of an oil ring groove in such a way as to be located below the center line of the piston body. Both ends of the oil drain hole are set lower than the lowest portion of a piston head. Therefore, it is possible to prevent lubricating oil from entering the combustion chamber when the engine stops, without providing a whirl-stop on piston rings.

Abstract: An arrangement and structure for an oil pan system to permit mounting a vertical in-line engine in a vehicle in a horizontal or nearly horizontal attitude includes a cylinder block of the engine having an opening on the side wall thereof, a cover attached to the cylinder block where an ordinary oil pan is usually mounted, an adapter plate fastened to the lower side wall of the cylinder block and bottom of the cover, and an oil pan attached to the lower surface of the adapter plate. The adapter plate allows the oil pan to extend and always remain below the cylinder block, so that the return paths from the lubricated portions of the engine to the oil pan are shortened.

Abstract: An idle controller for an internal combustion engine which increases the idle setting of the engine and retards the idling timing whenever the heater is operated, so that in a particular embodiment in a vehicle which further includes an air conditioner the idle controller increases the idle opening of the throttle valve whenever either the heater or the air conditioner is operated, and retards the timing when the heater is operated.

Abstract: Disclosed is a secondary air supplying device of an internal combustion engine having an exhaust passage provided with a catalyzer for purifying exhaust gas. The device includes a first air injection port provided in the exhaust passage at the upstream side of an exhaust manifold and a second air injection port provided in the exhaust passage at the upstream side of the catalyzer. Under the engine warming operating condition only when the engine speed is abruptly accelerated, or during a predetermined time interval after the engine is warmed, is secondary air injected into the exhaust passage from the second air injection port. When the engine is in the other operating conditions, secondary air is injected into the exhaust passage from the first air injection port.

Abstract: Disclosed herein is an apparatus for cleaning the exhaust gas of an internal combustion engine, which apparatus includes an exhaust gas recirculation system provided with a back-pressure control mechanism for maintaining a predetermined constant pressure of recirculated exhaust gas in a recirculation passageway, and an air injection system connecting an air pump with an exhaust system of the engine. An air-flow control valve having two vacuum chambers arranged between the air injection system and the exhaust gas recirculation system for controlling, in two stages, the amount of air diverted from the air injection system to the recirculation passageway. One of the chambers is directly connected to a vacuum source in the intake system of the engine. While the other is connected, via a vacuum delay unit, to the vacuum source.

Abstract: An apparatus for preventing the discharge of evaporated fuel gas including a charcoal canister for absorbing and temporarily storing fuel gas, a purge port placed in the intake passage of the carburetor of the engine, a passage for evaporated fuel connecting the purge port with the charcoal canister so that the evaporated fuel that has become stored in the charcoal canister is supplied to the engine during operation of the engine by means of the negative pressure in the air passage, a second purge port which opens to a venturi section of the carburetor, a second passage for evaporated fuel which connects the second purge port with the charcoal canister and a check valve which is placed in the second passage which allows a flow only in the direction of the venturi section.

Abstract: A secondary air control system for an internal combustion engine having an exhaust system provided with exhaust gas treating means adapted for secondary air injection and including a relief valve includes a mechanism which keeps the relief valve open after the valve is opened by a predetermined pump discharge pressure, until a predetermined lower pressure is reached.

Abstract: Disclosed is an internal combustion engine with an exhaust gas recirculating system. The engine has a movable shroud. The shroud is positioned near the rear surface of the valve head of the intake valve so as to obstruct a part of the mixture stream flowing through the valve opening of the intake valve for creating the swirl motion of the mixture in the combustion chamber when the amount of the recirculated exhaust gas is larger than a predetermined level. The shroud is retracted to a position where the shroud does not obstruct the mixture stream flowing in the intake port of the engine when the amount of the recirculated exhaust gas is smaller than said predetermined level.

Abstract: An exhaust gas purifying apparatus for use in connection with an internal combustion engine, especially for an automobile. The apparatus includes a fluid flow changeover valve having an outlet connected to the intake system of the engine, an exhaust gas inlet connected to the exhaust system and an air inlet connected to a source of pressurized air, for example, an air pump driven by the engine. When rotation of the engine is slow and consequently the output pressure of the air source is low, supply of the air to the intake system is stopped but exhaust gas is supplied thereto, whereby generation of nitrogen oxides (NOx) is reduced. In response to increase in the engine speed, air and exhaust gas are both supplied to the intake system until the output pressure of the air source increases to a predetermined value, whereby uniform combustion of fuel-air mixture in cylinders is maintained.

Abstract: An exhaust gas recirculator for purification of emission from an internal combustion engine characterized in that an exhaust gas recirculation pipe links the intake manifold and the exhaust pipe connected to the engine cylinder, midway in which is inserted a recirculation control valve acting by the negative pressure of the intake manifold. An orifice with its sectional area variable in the displacement direction of the valve body is provided in the chamber of the recirculation control valve, and a desired flow characteristic of the exhaust gas is obtained by the setting of the orifice configuration.

Abstract: An exhaust gas purifying device wherein exhaust ports in the respective cylinders of an engine communicate with the respective inflow passages of a thermal reactor, and more secondary air flows into the inflow passage at the part of the thermal reactor with sufficient thermal diffusion than into another inflow passage.Further, a taking-out port for the exhaust gas to be recirculated is provided at the exhaust port which communicates with the inflow passage at the part of the thermal reactor exhibiting insufficient thermal diffusion.

Abstract: There are provided an improved thermal reactor apparatus for, and an improved method of, purifying exhaust gases, particularly from a motor vehicle, wherein thermal oxidation and catalytic oxidation of the CO and HC contents of the exhaust gases and/or catalytic reduction of the NO.sub.x contents of the exhaust gases are effected within an environment such that at least some of the components of the reactor exposed to the exhaust gases are coated with and/or made of a catalytic alloy capable of acting as a catalyst for oxidation of the CO and HC contents of the exhaust gases and for reduction of the NO.sub.x contents of the exhaust gases.In the preferable embodiment of the invention, the above mentioned environment comprises an upper stream zone occupied by a rich reducing gas mixture, including the starting exhaust gases, and a lower stream zone occupied by a rich oxidizing gas mixture, including the resultant gases from the upper stream zone and additional air.